Preparation and characterization of alumina supported nickel-oxalate catalyst for the hydrodeoxygenation of oleic acid into normal and iso-octadecane biofuel

摘要

In this study, nickel Ⅱ oxalate complex (NiOx) was prepared by functionalization of nickel with oxalic acid (OxA) and incorporated into Al_2O_3 to synthesize alumina supported nickel oxalate (NiOx/Al_2O_3) catalyst for the hydrodeoxygenation (HDO) of oleic acid (OA) into biofuel. The synthesized NiOx/Al_2O_3 was characterized and the X-ray fluorescence and elemental dispersive X-ray results showed that NiOx was successfully incorporated into the structure of Al_2O_3. The X-ray diffraction and Raman spectroscopy results confirmed that highly dispersed Ni species are present in the NiOx/Al_2O_3 due to the functionalization with OxA. The catalytic activity of the NiOx/Al_2O_3 on the HDO of OA produced a mixture of 21% iso-C18 and 72% n-C18 at a 360 ℃, 20 bar, 30 mg NiOx/Al_2O_3 loading pressure and gas flow rate of 100 mL/ min. The presence of i-C_(18) was ascribed to the OxA functionalization which increased the acidity of NiOx/Al_2O_3. The NiOx/Al_2O_3 reusability study showed consistent HDO ability after 5 runs. These results are promising for further research into biofuel production for commercialization.